Good morning bloggers,
It is ridiculously cold outside as we set a record low this morning of -7°, breaking the old record by 6 degrees. The coldest temperature ever recorded in March was -10 on March 4th. We have some warmer days ahead of us, but it will be another roller-coaster ride of weather ahead.
Kansas City Weather Time-Line:
- Today: Mostly sunny & very cold. High: 14°
- Tonight: Clear with light south winds returning at around 3 to 10 mph. Low: 3°
- Tuesday: Mostly sunny and much warmer. High: 33°
- Wednesday: A weak storm system could bring us some light precipitation in the form of rain or snow. High: 36°
On Saturday, the temperatures dropped into the single digits at the surface, and all the down to 1° during the noon hour. We just experienced the coldest March high temperature, with a 5°F high, officially in Kansas City since records began taking place in the 1880s. That is a record, but the most amazing thing is what happened with the precipitation. The 1000-500 mb thickness was 534 decameters, with an 850 mb temperature of -13°C, and the surface temperature of 2°F by 8 AM, and it was SLEETING! It was sleeting heavily along and south of I-70 across the south KC metro area. It sleeted for almost 12 hours. There was one small warm layer at around 7,000 feet up, but this is near the precipitation generating zone. It was a temperature profile that would be tough to ever match again. The sleet cut into snowfall totals and created a nightmare for the weather forecaster who predicted high amounts of snow, and I will discuss this in-depth below.
Here is a Youtube clip from Norman, OK. Now, we didn’t have thundersleet, but our sleet was an incredibly rare experience: Thundersleet in Norman, OK
Look at the frozen pond on this March 3rd morning:
The pond froze over during the day on Sunday. That is incredible. I have never seen that pond freeze over during a day that it was windy and snowing. Incredible, and the fact that it was a March day. Only two other winters have had below zero readings in December, January, February, and March. It happened this season, and in 1979-80 and 1961-62 winters.
How did it sleet and not snow with temperatures so cold?
Sleet for 12 hours with temperatures dropping through the single digits to near zero? Has this ever happened in the world before? Many of you gave the weather forecaster a rough time yesterday. Was it deserved? Perhaps! We were forecasting high snowfall totals the day or two before the storm moved in. Was the forecast a bust? I would consider the snowfall totals part of the forecast quite a bit off. The temperature part of the weather forecast was almost perfect! The amount of precipitation forecast was just a bit under what was predicted but not bad at all. The forecast for sleet was strongly stressed for days, even hours before the precipitation started, so that part of the forecast was quite accurate. And, a significant winter storm and Arctic outbreak just happened in the Kansas City viewing area and it was impacting to most of us and our pets. So, this was not a busted forecast, just one part of it was, and it is unfortunately the most important part of a snow storm forecast.
Let’s look at precipitation forecasting and one reason why it is almost impossible to get it right every time. I feel that the 41 Action Weather team has done an excellent job at predicting snow, not just this season, but the past few years. Trying to predict the exact amount of any precipitation for any type is really difficult. Let’s say you come up to me and say, “Gary, I really need an inch of rain on my yard tomorrow. Do you think it will rain one inch?” And, then I may respond, “I think you will get somewhere between two to three tenths of an inch, but if you get under one of those thunderstorms, then you may get your inch or maybe even two inches of rain.” That person then may say, “thank you for the forecast”. And, then what happens the next day? They get around 1/2″ of rain. Was the forecast correct? Now let’s change that exact same discussion into snow. The person asks, “Gary, how much snow do you think we will have?”. And, by the way this happened around 100 times to me in the past three days. I respond by saying, “This is a difficult one as sleet may cut into snowfall totals. I am not really sure, but I think you could see at least 2 or 3 inches of snow. But, if you end up in one of these heavier bands of snow, then you could end up with 10″ or maybe even 20?”. When I said this to people on Saturday they just gave me looks as if I am crazy. Do you see that it is really the exact same thing as the rainfall forecast? If you use the normal 10 to 1 ratio, then 2 or 3 inches is equivalent to two or three tenths of an inch of rain. 10″ of snow is equivalent to the one inch of rain that person wanted. And, 20″ would be equivalent to two inches of rain. But, the person needing the inch of rain would not throw us to the wolves like many of you tried to do yesterday. Does this make sense? If we had to forecast exact rainfall amounts every time, then, well, I am not sure what would happen. Of course we try very hard to make accurate rain and snow predictions and we actually do a pretty good job. This one was just a tough one, and we knew it well before the storm arrived.
So, what happened? Did you know that weather balloons are launched twice a day at over 500 points across the world, one of which is Topeka, KS? As the weather balloon travels up it gathers weather information that is used to help initialize the computer models that we use in forecasting the weather. The Skew T diagram is a plot of the balloon sounding and used by meteorologists to analyze the data. The plot shows temperature and dew point temperature with height using pressure to indicate the height level. Take a look at this sounding from Topeka at 12z, or 6 AM Saturday morning:
Our surface temperature was in the single digits, way below zero Celsius. And, the atmosphere was moist all the way up. We had an incredible amount of moisture considering the very cold temperatures. But,look at that one small layer that went above freezing for around 1,700 feet. From 6,407 feet above us to 8106 feet above us there was a layer just barely above 32°F (0°C). But, this level is most often where precipitation forms, rain and snow. It can vary a lot, but usually this is near where conditions become favorable for rain and snow formation. And, if it was developing in that 1700 foot layer, then there is a good chance that much of the precipitation formed as rain way up there. Some of it was likely melted snowflakes as well. Then the rain fell through the much colder air below 6,407 feet and the raindrops froze into sleet. The 1000-500 mb thickness had dropped to around 5,340 meters by 9 or 10 AM, and yet it was still sleeting on the south side of the city. This EXTREMELY rare combination is what ended up cutting our snowfall totals by at least four to six inches. In other words, our 2 to 4 inch amounts would have easily have been in the forecast 6 to 10 inch range. The weather forecaster had a very unlucky day!
So, it really wasn’t a busted forecast overall, but we absolutely ended up wrong on the snow part of the weather forecast. This is one of the storm systems we pegged on our long range forecast made in the middle of January. This is the graphic we showed on the air. And, the only storm that didn’t quite show up was in that 14th to 17th time-frame. We were four out of five, or 80% accurate, which included predicting the big early February storm, and then the 50 day forecast for this most recent storm system.
What lies ahead? The weather pattern continues to cycle and we will discuss this in the Weather 2020 blog, and in here from time to time. Winter may get a break, but we have quite an interesting ride of weather ahead of us as we head into the Super Bowl part of the weather pattern later this month.
Have a great day. Please let us know what you think about the Skew T diagram. Did it make sense to you? If you have any questions I will try to find the time to answer them later today. Thank you for spending a few minutes reading the Action Weather Blog.